using System;
using JD.Collections.Interfaces;
using JD.Kernel.StaticHelpers;

namespace JD.Collections.ObjectModel
{
    /// <summary>
    /// A read-only implementation of the <see cref="IObservableCollection{T}"/> interface.
    /// Methods that modify the collection throw a NotSupportedException, methods that don't
    /// modify are forwarded through to the wrapped collection.
    /// </summary>
    [Serializable]
    public class ReadOnlyObservableCollection<T> : ReadOnlyCollection<T>, IObservableCollection<T>
    {
        #region Variables

        private readonly IObservableCollection<T> m_wrappedCollection;

        #endregion

        #region Constructor

        /// <summary>
        /// Creates a ReadOnlyCollection wrapped around the given collection.
        /// </summary>
        /// <param name="wrappedCollection">Collection to wrap.</param>
        public ReadOnlyObservableCollection(IObservableCollection<T> wrappedCollection)
            : base(wrappedCollection)
        {
            Throw.IfNull(wrappedCollection, "wrappedCollection");
            m_wrappedCollection = wrappedCollection;
        }

        #endregion

        #region Properties

        /// <summary>
        /// Access the internal wrapped collection.
        /// </summary>
        protected IObservableCollection<T> WrappedCollection
        {
            get { return m_wrappedCollection; }
        }

        #endregion

        #region IObservableCollection<T> Members

        public bool IsUpdating
        {
            get { return m_wrappedCollection.IsUpdating; }
        }

        void IObservableCollection<T>.BeginUpdate()
        {
            MethodModifiesCollection();
        }

        bool IObservableCollection<T>.EndUpdate()
        {
            MethodModifiesCollection();
            return false;
        }

        public event EventHandler<CollectionChangedEventArgs<T>> CollectionChanged
        {
            add { m_wrappedCollection.CollectionChanged += value; }
            remove { m_wrappedCollection.CollectionChanged -= value; }
        }

        #endregion
    }
}